Manufacture of articles of iron or steel.



UNITED STATES PATENT orrion ERASTUS E. PIERCE, OF NEW BRIGHTON,PENNSYLVANIA, ASSIGNOR TO STANDARD HORSE NAIL COMPANY, OF NEW BRIGHTON,PENNSYL- VANIA, A CORPORATION OF PENNSYLVANIA.

MANUFACTURE OF ARTl CLESOF IRON OR STEEL.

Specification of Letters Patent.

Patented Aug. 7, 1906.

Application filed June 6,1903. Serial No. 160,377.

To all whom, may concerm Be it known that I, ERASTUS E. PIERCE, acitizen of the United States, residing at New Brighton, in the county ofBeaver and State of Pennsylvania, have invented certain new and usefulImprovements in the Manufacture of Articles of Iron and Steel, of whichthe'following is a specification.

In the ordinary processes of making small articles, such ashorseshoe-nails, of iron or steel the blanks are forged and thencoldrolled, or they are forged and rolled and drawn hot; but in eithercase the hot blanks or nails are deposited in a metallic receptacle andallowed to cool. This results in annealing the blanks or nails and alsoin the formation of a coating or scale of oXid, which must besubsequently removed by tumbling, which requires much time and resultsin a very material loss of strength in the nails.

I have found by many practical operations that if the metal instead ofbeing allowed to cool slowly, as heretofore, is suddenly cooled while atthe forging heatthat is, a heat above a low red heatthe formation ofoXid is to a great extent prevented, and by then cold-forging thearticles are very much stronger than when produced as usual, manypractical tests showing an increase of tensile strength of overthirty-four per cent. as a result of these operations. The articles arealso more elastic and take a brighter finish. Steel or iron is employed,but with such a low percentage of carbon-that is, .40 or under as willprevent hardening when rapidly cooled. If soft steel, such asSiemens-Martin or open-hearth, is used, care should be taken that it isso low in carbon that the sudden cooling will not temper and harden thearticles, the object of thus suddenly cooling not being to harden oranneal the product, butto prevent the annealing and the formation of thethick scale which always results from slow cooling.

Difierent means may be employed for suddenly cooling the nailsas, forinstance, by directing a spray of water by an air-current upon thearticles as-they fall from the ma-- chine or while in the pot orreceptacle. Such cooling results in reducing the temperature to not over212, above which water could not be employed, and generally to atemperature suflicient to handle by hand. The exact degree to which thearticles are cooled will depend upon the temperature of the water orother liquid employed, it only being essential to secure a rapid coolingfrom the forging heat to a comparatively cold condition.

I am aware of the practice of treating metal by first heating and thenwhile at a low red heat immersing it suddenly in water. This results inannealing and in reducing the tensile strength of the metal and also inreducing its elasticity.

I am also aware of the fact that certain metals high in carbon have beensubjected to a sudden cooling; but the result in such case is to hardenor temper the same, and this latter treatment is therefore practicablefor use so far as any effective result is secured in the treatment ofwhat are known as tool-steels or cast-steels, which has for its'objectto render them suitable for dies or to give hard cutting edges. 4 v

The object of my invention is not to harden thearticles in the sense oftempering them nor to anneal them, and thus impair their elasticity andtensile strength, but to increase their tensile strength and render themmore elastic, while also imparting to them a great degree of ductility,and I have discovered that the sudden cooling of the metal while it isabove a low red heat results in securing these characteristics in theartiole and that if the article thus produced is then further treated bycold-forging a greater degree of density and stiifness is secured.

Without limiting myself to the use of any specialmeans of cooling, Iclaim 1. The within-described improvement in the manufacture of articlesof wrought iron or steelof a grade below a tempering grade, consistingin 'subj ecting the metal while above a low red heat to a treatmentwhereby it is suddenly cooled to a temperature of approximately lessthan 212, and finishing without reheating, substantially as set forth.

2. The within-described improvement in the manufacture of articles ofwrought iron or steel 'of a grade lower than a temperin In testimonywhereof I have signed my grade, consisting in subjecting the meta nameto this specification in the presence of While above a 10W red heat tomeans for sudtwo subscribing Witnesses. denly coolin the same to atemperature of ERASTUS E. PIERCE.

5 approximate y less than 212 and then fin- Witnesses:

ishing by cold-forging, substantially as set FRANK REED, forth. JOHNREAD MINER.

